The Internet Was Wrong: Short Chainstays Suck*

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7/18/2016 11:18 AM
Edited Date/Time: 7/18/2016 12:46 PM

The Internet Was Wrong: Short Chainstays Suck*

****Disclaimer - Full on bike geekery below - eyes *may* glaze over while reading***

First, a story. Many years ago the bike world was convinced the shorter the rear end of the bike, the better it would corner. Or rather, the easier it was to change direction.The internet forums were rife with thread after thread looking for a bike with the shortest rear end one could cram into a bike. The first iteration of the Specailized Demo circa 2005 really reflected this trend on the longer travel side of things with 16.9" stays. Coincidentally, me owning this bike correlated to my last season of DH racing. My times sucked, I never felt comfortable, and couldn't figure out why.

Fast forward to today, bikes have grown substantially in overall length but many manufacturers are still spec-ing incredibly short rear ends. As many of you know, I ski 6 months a year. This trend of long bikes and short CSs would be akin to skis getting substantially longer but mount points staying in the same location (same amount of tail). For the skiers out there, one can only imagine how silly it'd be to ski a 195 with a -31CM mount point - in short, it'd be terrifying.

Your top two finishers this weekend were both on bikes with "long" (by today's trail bike standards) chainstays. To add, neither of these riders are super tall and both (likely) riding medium frames.

Richie Rude: SB 6c medium - 17.4" chainstays
Sam Hill: NukeProof Mega (guessing a medium) 17.5" chainstays


First things first, yes, both Sam and Richie have talent that is far beyond what any of us that hang around Vital can comprehend, let alone emulate. Put another way, its the the artist, not the brush, and no amount of bike geekery will turn one of "us" into one of "them".

Still, as bikes have grown in length, I've noted this strange push and pull. On one hand I feel much more comfortable on the bike. (EG, my knees don't hit my handlebar, and I no longer look like a circus bear riding a tiny bike) On the other hand its become increasingly hard to get enough weight on the front tire.

When bikes had wheelbases that were 2-3" shorter than today's standard, it would make sense that a short rear center would offer a fairly balanced ride, especially in the small and medium sizes. However, as bikes have grown in front center, manufacturers have stuck by the internet driven adage that "long chainstays suck". Don't get me wrong, for a number of bikes, short rear centers make sense. But for bikes built for aggressive riders trying to go fast, short rear centers are dream crushing, especially in larger sizes.

From a race results perspective, one needs to go no further than Aaron Gwin's first season on Specialized to see what a shorter rear end can do for one of the fastest guys on the planet (he had a bad season until they lengthened the rear end). Minnaar famously had a few breakout races on the now-legendary (yeah, I said it) XXL V10 (with ghastly long 17.75" stays). Even Sam Hill has lengthened his Nukeproof DH bike's rear end to get more weight on the front tire.

This post is meant as a call out for manufacturers to start recognizing this need for longer rear ends to compliment the longer front end. Simply, longer CS measurements are needed to balance the bike. Ideally, each size would have a different rear center (norco does this - getting longer as the size goes up - though they are still too short) to keep this balance in check, but I realize this can be extremely cost prohibitive.

There are objective ways to "test" for this balance, which I won't go into here. But yes, in an XL size, I'd like to see a "throwback" to 17.5-17.75" stays.

Likely? Probably not. But maybe one or two manufacturers will take note and start offering stuff that really is balanced in the larger sizes. The real irony is longer stays can actually make a bike corner **better**, so long as its all kept in proportion.


Without being too long winded, I leave you with the wisdom of Walter Sobcek...(am I wrong?)


Discuss amongst yourselves.

(PS, Team Robot said this a year ago)

*short chainstays are totally legitimate in kids bikes, short people bikes, XS bikes, dirt jumpers, and "I only ride park - bikes"











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7/18/2016 12:32 PM

i fully support this statement.

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7/18/2016 1:24 PM



maybe troy could win another WC with one of these


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7/18/2016 1:44 PM
Edited Date/Time: 9/11/2018 7:37 AM

I respectfully disagree. I am my own "Bike manufacturer." and at 6'7" tall, my current DH bike has 16 3/8" chain stays and I love it. With front centers getting longer and longer, and mine are plenty long, a short chain stay keeps the overall wheel base reasonable. And yes they do help in quick cornering. If stability is an issue, get stronger.

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7/18/2016 1:59 PM
Edited Date/Time: 7/18/2016 2:27 PM

Big Bird wrote:

I respectfully disagree. I am my own "Bike manufacturer." and at 6'7" tall, my current DH bike has 16 3/8" chain stays and I love it. With front centers getting longer and longer, and mine are plenty long, a short chain stay keeps the overall wheel base reasonable. And yes they do help in quick cornering. If stability is an issue, get stronger.

Respectfully, I'd argue you are contradicting yourself. Keeping a longer bike's wheelbase in check with short stays would be akin to keeping a snowboard length in check by cutting off a chunk of the tail. My entirely too long "rant" was essentially saying to keep these longer bikes balanced, CSs need to grow in proportion to front center/head tube angle, regardless of what the wheelbase is. My $0.02 is the bike's wheelbase is a total "side effect" number (of appropriate CSs, FC and HT). Not a number one should, by itself, shoot for.

Have you tried longer stays? Remember, I'm not arguing I need long stays for stability, but to more naturally weight the bike properly. I'm actually arguing I turn a bike **better** with longer stays (to a point) as it allows me to get my weight on the front of the bike while remaining in a more neutral riding position.

Put your front and back wheel on two scales. Have someone support the bike. Climb aboard and get in your attack position. I'd wager you are weighting the rear wheel a lot more than your front, even for a downhill bike. (I'd argue 48/52 front/back is appropriate for trail/enduro, 45/55 DH)


EDIT: one of the difficult things about this is body types/riding styles/etc are heavily going to play into the results. Hence, maybe what you are building is great for you...but I'd still be curious if you've really played with CSs all that much - and extremely curious what the scales say.





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7/18/2016 2:42 PM
Edited Date/Time: 7/18/2016 2:56 PM

I agree. Short chainstays are just a mutated remnant from the "freeride" marketing toxic waste dump, along with high bottom bracket heights, slack seat-tube angles, short front-centers, detachable fullfaces, front derailleurs and tall socks.

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7/18/2016 3:02 PM

Colin McCarthy wrote:

I agree. Short chainstays are just a mutated remnant from the "freeride" marketing toxic waste dump, along with high bottom bracket heights, slack seat-tube angles, short front-centers, detachable fullfaces, front derailleurs and tall socks.

Agreed. We all wanted to boil bike handling down to overly simple isolated variables as opposed to looking at the tool as a whole.



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7/18/2016 3:47 PM

Couldn't agree more with what's been said here really. The best bike I ever had was a 2003 Yeti DH9. Long in the front, long in the rear, and that thing inspired confidence and was more planted in the corners than any modern bike I've ridden.

Also I think you touched on something in your recent post about riding styles having an effect on weight balance etc. It seems that head tube angles have settled down now but we went through a period of bikes getting slacker and slacker because 'that's what the pros ride'. Well I'll wager very few of us have the confidence and ability to weight the front wheel of a bike like the pros do. Trends have a way of sending us down a path that might not actually beneficial for the regular guy.

When a race car is set up, it is corner weighted, with ballast moved around to equalise weight distribution across all four wheels. I understand that the majority of the mass of a bicycle+rider is the rider, but I don't see why this sort of logic isn't applied more at the top level of our sport. Maybe it is in a way, but probably more through feel, and 'tweaking' the setup rather than some kind of quantitative analysis. I know they are starting to make a joke about Minnaars fiddling with his setup by tiny amounts here and there, but he is finely tuned into his equipment and I'm sure it makes a difference. If only there was a way to actually measure the effects of those changes.

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7/18/2016 3:55 PM

Oz_Taylor wrote:

Couldn't agree more with what's been said here really. The best bike I ever had was a 2003 Yeti DH9. Long in the front, long in the rear, and that thing inspired confidence and was more planted in the corners than any modern bike I've ridden.

Also I think you touched on something in your recent post about riding styles having an effect on weight balance etc. It seems that head tube angles have settled down now but we went through a period of bikes getting slacker and slacker because 'that's what the pros ride'. Well I'll wager very few of us have the confidence and ability to weight the front wheel of a bike like the pros do. Trends have a way of sending us down a path that might not actually beneficial for the regular guy.

When a race car is set up, it is corner weighted, with ballast moved around to equalise weight distribution across all four wheels. I understand that the majority of the mass of a bicycle+rider is the rider, but I don't see why this sort of logic isn't applied more at the top level of our sport. Maybe it is in a way, but probably more through feel, and 'tweaking' the setup rather than some kind of quantitative analysis. I know they are starting to make a joke about Minnaars fiddling with his setup by tiny amounts here and there, but he is finely tuned into his equipment and I'm sure it makes a difference. If only there was a way to actually measure the effects of those changes.

You echo some of the thoughts I've recently had. It'd be rad if there was someway to actively monitor how much weight I'm putting on each tire or the forces on each tire at any given moment. That would really help an engineer build better more natural bikes.

As far as slack head tube angles go, I too agree. Unless you are charging super steep tracks and have the balls to stick your head way over your front wheel, they can be challenging to ride. That said, I've found slacker HTs easier to ride as the rear grows. I also believe slack head tube angles are excellent for newer riders as it can keep them from OTBing it too much. Its us middle-of-the-road riders that really don't benefit from uber slack bikes.

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7/18/2016 5:00 PM

I've been really feeling this lately. Going from my tracer to riding a carbine 29 (17.25-17.5) the bike felt far more stable at speed. I hopped around on my buddy's xxl V10 and the 17.7 chainstay mannyd no problem. I'm ready to sacrifice a tiny bit of agility for more stability

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7/18/2016 6:03 PM

I agree with this if we are talking purely about going very fast downhill. When doing technical climbs on the other hand, a rearward weight bias gives more traction (this is also true for motor vehicles, maybe not so much for skis). Nino Shurters new XC bike for example has the slightly shorter stays.

Looking at the EWS example, it makes sense to have longer bikes for maximum stability since they are only timed going down, and the climbs are fire roads or shuttle/lift assisted (also the reason they can get away with 180mm forks). For those of us that pedal an up on mixed terrain as well as going down a compromise between long and short is needed.

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7/18/2016 6:11 PM

Oh, please. Your rant boils down to: I want a slower-handling bike. That's fine, you like what you like. I happen to like a quicker-handling bike.

All this pontificating about front-rear weight distribution is a little ridiculous. If you keep the wheelbase the same and go from 16.9" chainstays to 17.5" chainstays, that amounts to moving your feet 0.6", while keeping everything else the same. Given that when standing on the pedals you can move your whole body back and forth, the total change in your center of mass position is really small. Your body's max rearward position is limited by your arms, not your BB position, and max forward position is irrelevant, since you never go there.

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7/18/2016 6:55 PM

Unfortunately many brands will keep short rear ends to help shit cyclists feel good on a bike. Riding around turns and steering around them rather than picking a smart line and edging is a ton easier with a short rear end. Also, how much easier is it to wheelie a bike with 420mm chainstays than 440.... Big companies will always want "Joe with the money" to feel like a rockstar when he is hucking curbs in front of the bike store, when he is looking to make his anual upgrade... Those f***ers are killing frame design progression.

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7/18/2016 7:35 PM

Banshee Legend - 17.5 inch Chainstays, just saying...

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7/18/2016 8:25 PM
Edited Date/Time: 7/18/2016 8:26 PM

My 05 Prophet CS measurement comes in at 16.5" but that's with a shorter front and 90-110mm stems. Funny how much geo changed in 11 years. Swung one way and now to the other in the long slack front end department. Now with such short CS measurements in favor I can see it middling out. 17-17.5" seems about right in theory for larger wheels than for my "dinosaur" 26er. Something else to consider if I convert to 27.5. (Can be done on a Prophet)

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7/18/2016 9:08 PM

Colin McCarthy wrote:

I agree. Short chainstays are just a mutated remnant from the "freeride" marketing toxic waste dump, along with high bottom bracket heights, slack seat-tube angles, short front-centers, detachable fullfaces, front derailleurs and tall socks.

The seat tube angles even with a long inseam that causes all sorts of power and positioning issues for me.
Does not feel right slack.

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7/18/2016 10:27 PM

I think even a year ago I would have argued very much the other way, but since then I have improved my riding ability greatly and my 2014 stumpjumper 29 with 455 mm (17.9 in) chainstays that used to feel like it was just sluggish actually feels great every time I ride it. I have learnt how to manual and wheelie it now, and it's just fun.

On the other side of the coin, I love having short stays on my Demo 8 because I know I'm not fast, and don't try to be, that bike is purely for fun.

So I think it boils down to - do you want to have fun doing stupid shit and go slow? Then short is great. Do you want to have fun going fast? Then long is great.

But as has already been established, it needs to be proportional to rider size / bike size. Short TT long rear end is just as silly as Short rear end long TT.

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7/18/2016 11:15 PM

SJP wrote:

Oh, please. Your rant boils down to: I want a slower-handling bike. That's fine, you like what you like. I happen to like a quicker-handling bike.

All this pontificating about front-rear weight distribution is a little ridiculous. If you keep the wheelbase the same and go from 16.9" chainstays to 17.5" chainstays, that amounts to moving your feet 0.6", while keeping everything else the same. Given that when standing on the pedals you can move your whole body back and forth, the total change in your center of mass position is really small. Your body's max rearward position is limited by your arms, not your BB position, and max forward position is irrelevant, since you never go there.

Dude, 0.6" is huge. Put yourself and your bike on the scales and check the difference when, in riding position, moving your upper body back and forth. Weight balance is so fragile, you can easily achieve a delta of ten pounds. Do yourself a favor and check it out, it's an eye-opener.

From seeing how much the weight balance changes dynamically some may say "so then simply adjust weight balance by using your riding position". But I digress, a better balanced bike still puts you in a better position to begin with and THEN you can really start to play with your upper body.

So, definitely support the OP's statement. Just got myself a Giant Glory in S (me 5'7"), found out it's way longer than Giant's geometry table suggests, and installed a plus-1-degree headset. Shortened front center, slightly longer reach, havin' a blast in turns now!

Anyway, the longer chainstay topic is easy to get your head around. But what happens when you go to longer reach values (at constant CS)? Don't you get to a point with increasing reach, where the upper body is tilted so much to the front as to have the same effect of weighting the front wheel?

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7/18/2016 11:25 PM

100% agree. Aggressive riders trying to go fast (and not just racers) or anyone who wants a bike that actually handles need longer chainstays on their bikes. There will always be the odd ball that rides a little differently and somehow able to make short chainstays work. A lot of riders that still thinks short chainstays win don't know how to manual or just haven't tried a proper bike with proper balanced geometry. Even less aggressive riders on 'trail' bikes can benefit from longer chainstays, since the whole short chainstay thing has gone way too far - we shouldn't be thinking of it as making them longer - just correcting terrible geometry to the way it should always have been. Short chainstays suck. I'm 5'6" and I like 440+ on a medium (430 reach) bike with a 64° HA - that's a trail bike with 150mm travel.
If you know what you like that's cool, I'm not telling you guys what to ride but if you've not tried it then you really should.
Ps I've been saying this for years but who's counting ;-)

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7/19/2016 12:23 AM
Edited Date/Time: 7/19/2016 2:10 AM

I think it boils down to people riding what they're used to. If it's different, there will be "growing pains" in getting used to it. Trying to use the bike in a way similar to their last, and seeing it struggle (wheelies, manuals, etc.), is seen as a glaring downside, despite it possibly being faster and more capable overall. Maybe people see things not from a race point of view, but a stoke point of view. If the bike's so good that it dumbs down the trail, on top of looking dull when caught on camera (see Greg Minnaar), it seems boring once the thrill of doing something new goes away.

While longer CS has better performance over raw chunky terrain, that's not necessarily where people have fun. People will ride trails conveniently located close to home. Such places tend to get new lines shaped into them that suit their current bikes. This is how park style riding is sort of born.

Can argue either way. The short CS crowd have their 50:01 movement. What's the longer CS crowd have? Using race results and anecdotal evidence saying you're a better ride on longer CS just isn't as rad as styling it out, I guess.

I thought my long CS bike was a ground hugger. Excellent for control, but numb to the point that speed was its only redeeming point. Traded it out for a hardtail, and now back on a medium-length CS (17.0") FS bike as sort of a compromise. One thing I certainly don't miss is how hard the rear wheel was taking an absolute pounding, getting pinch flats, etc. with 420mm (16.5") CS.




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7/19/2016 12:48 AM
Edited Date/Time: 7/19/2016 12:49 AM

Serge-W wrote:

Dude, 0.6" is huge. Put yourself and your bike on the scales and check the difference when, in riding position, moving your upper body back and forth. Weight balance is so fragile, you can easily achieve a delta of ten pounds. Do yourself a favor and check it out, it's an eye-opener.

From seeing how much the weight balance changes dynamically some may say "so then simply adjust weight balance by using your riding position". But I digress, a better balanced bike still puts you in a better position to begin with and THEN you can really start to play with your upper body.

So, definitely support the OP's statement. Just got myself a Giant Glory in S (me 5'7"), found out it's way longer than Giant's geometry table suggests, and installed a plus-1-degree headset. Shortened front center, slightly longer reach, havin' a blast in turns now!

Anyway, the longer chainstay topic is easy to get your head around. But what happens when you go to longer reach values (at constant CS)? Don't you get to a point with increasing reach, where the upper body is tilted so much to the front as to have the same effect of weighting the front wheel?

If you keep all other variables constant (eg. CS length, HT angle, stem length) then increasing reach should have the effect of putting more of the riders weight on the front wheel. The effect is pretty dramatic because the human head weighs around 5kg and this weight is high up/furthest forwards. This is why small changes can have such a big effect. The Mondraker Forward Geometry with the zero reach stem is an extreme example of this thought, but I have yet to see anybody running the zero reach stems in real life. Even with a super long front end, most riders don't find it possible to weight the front wheel with a zero reach stem, so there must be a sweet spot.

You can only go so long with the front end until the bike just becomes too big. Ok so the effect is to even out the weight distribution across the bike, but at what cost. The rider will be in a compromised position, limiting the effect of the rider, and the body won't function at it's most efficient or powerful. Increasing the front centre puts more force through the riders upper body, possibly increasing fatigue (relevant for all disciplines). The same weight distribution across the wheels could be achieved by lengthening the rear of the bike instead.

In my opinion, what you really want is the rider to be in a neutral position, where his whole body weight is distributed across the bike to suit his preference. There should be room for the rider to move his weight forward and backwards by enough to manoeuvre the bike in turns and over obstacles on the trail. As a personal test I stand on my bike in normal riding position and loosen my grip on the bars. I should be able to stand like this without feeling like I'm falling forwards or backwards.

I think we are reaching the limits on bike length, especially for downhill bikes. Think back to the recent world cup in Lenzerheide, where several riders were struggling with going OTB at the 'Plunge' in the woods. These are the top riders in the world, and even they were finding it difficult to manage such an extreme feature on the track. Tiredness + long bike makes it difficult to pick that front end up and react quickly.

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7/19/2016 1:36 AM

Oz_Taylor wrote:

If you keep all other variables constant (eg. CS length, HT angle, stem length) then increasing reach should have the effect of putting more of the riders weight on the front wheel. The effect is pretty dramatic because the human head weighs around 5kg and this weight is high up/furthest forwards. This is why small changes can have such a big effect. The Mondraker Forward Geometry with the zero reach stem is an extreme example of this thought, but I have yet to see anybody running the zero reach stems in real life. Even with a super long front end, most riders don't find it possible to weight the front wheel with a zero reach stem, so there must be a sweet spot.

You can only go so long with the front end until the bike just becomes too big. Ok so the effect is to even out the weight distribution across the bike, but at what cost. The rider will be in a compromised position, limiting the effect of the rider, and the body won't function at it's most efficient or powerful. Increasing the front centre puts more force through the riders upper body, possibly increasing fatigue (relevant for all disciplines). The same weight distribution across the wheels could be achieved by lengthening the rear of the bike instead.

In my opinion, what you really want is the rider to be in a neutral position, where his whole body weight is distributed across the bike to suit his preference. There should be room for the rider to move his weight forward and backwards by enough to manoeuvre the bike in turns and over obstacles on the trail. As a personal test I stand on my bike in normal riding position and loosen my grip on the bars. I should be able to stand like this without feeling like I'm falling forwards or backwards.

I think we are reaching the limits on bike length, especially for downhill bikes. Think back to the recent world cup in Lenzerheide, where several riders were struggling with going OTB at the 'Plunge' in the woods. These are the top riders in the world, and even they were finding it difficult to manage such an extreme feature on the track. Tiredness + long bike makes it difficult to pick that front end up and react quickly.

Glad to read this. Always had that nagging feeling in my head, what if I shorten CS and lengthen the reach to achieve a similar effect. But what you say makes sense in my world. Lengthening the reach should come at the cost of loosing some ability to stand in a neutral position on the bike (no weight on the handlebar).

One more thought, though. We're talking small differences here, but I recently went back to a slightly shorter front center (WB 1227, reach 410, CS 443) and feel it's great, my riding did improve noticeably this first half of the season.

But my last Bike, Turner DHR, had reach 424, WB 1232 and CS 442. So slightly longer front end. And on that bike I had moments that I cannot forget. Whenever I managed to stand up high in the bike (neutrally) and use body tension (core muscles) to rotate the bike in turns and keep the weight balance, then even the steepest, technical sections were a breeze. The bike really lit up in those moments and I could place the front wheel on anything and not loose traction. Me being me, aka not the supertrained dude, these moments were rare and depended on daily form.

I feel that this could be another feature that distinguishes the John Does from the Pros, apart from bike handling skills. Their core strength is probably way above what most of us have, so perhaps much higher body tension is another reason why pros can make long-reach bikes work much better. I suggest because of their fitness they keep composure and are less fatigued, despite a more forward position in the bike.

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7/19/2016 4:00 AM
Edited Date/Time: 7/19/2016 4:01 AM

Serge-W wrote:
Dude, 0.6" is huge. Put yourself and your bike on the scales and check the difference when, in riding position, moving your upper body back and forth. Weight balance is so fragile, you can easily achieve a delta of ten pounds. Do yourself a favor and check it out, it's an eye-opener.


Well, you've just repeated my argument back to me. Moving your ankles forward or back 0.6" is a tiny change compared to moving your upper body. The OP is misattributing the differences he feels to chainstay length in particular when they are more appropriately attributed to wheelbase and head tube angle.

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7/19/2016 4:09 AM

I beleive as well it should a bit longer, I like the Norco approach different CS according to size.

I had a demo 8 in 2012, the rear end was "diving" on jumps, I didn't felt too confortable on long jumps If you look at videos of sam hill and troy back in the day, it catch all the time my attention. It looks like they were all landing "hard" on back wheel. I believe the body weight distribution wasn't well center. it was deffinetly good to manual some bumps but never felt as good "safe" on jumping.

I ride a demo 2016 alloy this year, feel a lot better with the bike, the move on 650B and a little increase of the bike's length front and rear make me feel a little bit more center.

PS : I "don't pay" for bikes or if I do, I try to spend the less as possible, internet is a good alternative for that at the moment.. I prefer to spend my money in traveling the "world" with my bikes

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7/19/2016 5:12 AM

I totally agree with the topic in question. I've been a test rider for Pole Bicycles since day one. We've been making our bikes longer on the front and rear on every iteration. We've gotten a pretty good insight on how a small tweak in the geometry can have major effects on the bikes handling, since we are able to test on a wide range of options. Before actually riding the bikes we've always tried to measure the weight distribution with 2 scales under the tires, but that is just to get rough statistics on the changes. We mostly base our statistics on timed test runs on the trails we are familiar with.

What we've found out is that a longer bike isn't just to give you stability to keep you safe, it is simply faster. Every time we've tried a shorter reach or chainstays - after a timed run before checking the time - we've always felt like we hauled ass and it must have been fast, but the clock doesn't lie. With slack head angles, longer chainstays definitely help you weigh your front on the turns so you feel planted in the turns. And that in turn makes it possible to have a really slack head angle and feel comfortable on it. And the long chainstay also makes climbing with a slack head angle feel like a walk in the park

I think the silver bullet of chainstay length is to match it to the front-centre. If that isn's right then you have to compensate it while riding and usually coming out of corners you feel uncomfortable. My personal bike at the moment is a Large 140mm Pole Evolink (Reach 510mm/20.08in CS 456mm/17.95in) and I'm standing at 180cm (5.9 feet). Some might argue that it is too long for me but once you get comfortable with it there is no holding back. The longer bikes makes you more comfortable on highers speeds, rougher terrain, off cambers and in the corners the grip is endless. You end up leaning more in the corners, I feel like I lean in to the turn on the front tyre like I do on my KTM.

Longer chainstays on your AM/Trail/Enduro bike are key to letting your downhill bike collect dust in the garage.

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7/19/2016 5:27 AM

SJP wrote:

Serge-W wrote:
Dude, 0.6" is huge. Put yourself and your bike on the scales and check the difference when, in riding position, moving your upper body back and forth. Weight balance is so fragile, you can easily achieve a delta of ten pounds. Do yourself a favor and check it out, it's an eye-opener.


Well, you've just repeated my argument back to me. Moving your ankles forward or back 0.6" is a tiny change compared to moving your upper body. The OP is misattributing the differences he feels to chainstay length in particular when they are more appropriately attributed to wheelbase and head tube angle.

Not really. Ankle position has a similarly large effect, after all we are talking a good bit of body mass here as well. But it is something nobody really plays with. I realize you meant this hypothetically, but precisely because nobody plays with ankle position (and why would they?) shows why CS length does make a difference.

Totally agree that upper body movement has a huge effect. But as I said, neutral balancing of front and rear center puts you in a better place to begin with. Because CS length changes the general weight balance of the bike, irrespective of body position.

Whereas the effect of longer reach is not so clear cut. On one hand it drives the upper body more forward, but on the other hand it reduces the load on the front wheel, when looking at the leverages while standing in the pedals (without handlebar contact).

Look at @Oz_Taylor's comment. You can overdo it with a long reach, as you may find yourself forced to lean forward more heavily to keep pressure on the front wheel. With too long a reach you compromise that neutral position (the position where one can lift the hands off the handlebar while standing, but weight balance in the bike remains intact). But this effect may depend on the specific weight distribution of the rider's body, which will be slightly different for every rider. So chainstays longer is an easier way forward for fitting a bike imo.

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7/19/2016 6:09 AM

SJP wrote:

Serge-W wrote:
Dude, 0.6" is huge. Put yourself and your bike on the scales and check the difference when, in riding position, moving your upper body back and forth. Weight balance is so fragile, you can easily achieve a delta of ten pounds. Do yourself a favor and check it out, it's an eye-opener.


Well, you've just repeated my argument back to me. Moving your ankles forward or back 0.6" is a tiny change compared to moving your upper body. The OP is misattributing the differences he feels to chainstay length in particular when they are more appropriately attributed to wheelbase and head tube angle.

Serge-W wrote:

Not really. Ankle position has a similarly large effect, after all we are talking a good bit of body mass here as well. But it is something nobody really plays with. I realize you meant this hypothetically, but precisely because nobody plays with ankle position (and why would they?) shows why CS length does make a difference.

Totally agree that upper body movement has a huge effect. But as I said, neutral balancing of front and rear center puts you in a better place to begin with. Because CS length changes the general weight balance of the bike, irrespective of body position.

Whereas the effect of longer reach is not so clear cut. On one hand it drives the upper body more forward, but on the other hand it reduces the load on the front wheel, when looking at the leverages while standing in the pedals (without handlebar contact).

Look at @Oz_Taylor's comment. You can overdo it with a long reach, as you may find yourself forced to lean forward more heavily to keep pressure on the front wheel. With too long a reach you compromise that neutral position (the position where one can lift the hands off the handlebar while standing, but weight balance in the bike remains intact). But this effect may depend on the specific weight distribution of the rider's body, which will be slightly different for every rider. So chainstays longer is an easier way forward for fitting a bike imo.

I'm sorry, but you think moving ankles back and forth by 0.6" has a similarly large effect on weight distribution to leaning your upper body back and forth? It does not. Secondly, people do play with ankle position by moving their cleats on their shoes, most of which have a range that is a good fraction of that 0.6".

CS length changes the general weight balance of the bike, irrespective of body position? Again, 0.6" change in chainstay length, keeping wheelbase the same, has a very small effect on weight distribution compared to changing upper body position.

Longer reach drives the upper body forward? Not if you shorten the stem to keep the handlebars in the same place, which is how things are typically done. Sure, it lightens the load on the front wheel for a given angle of ground slope, but different people want their bikes optimized for different slopes.

Sure, you can overdo it with long reach or head tube angle, or chainstay length, or any design parameter. But, for the whole crop of modern bikes, these come down to preferences. Heck, just look at the change in weight distribution between flat ground, a 5 degree downslope, and a 10 degree downslope. It is bigger than swapping 0.6" of front-center for 0.6" of rear-center. Different people want their bikes optimized for different things, and ranting against some current bikes' chainstay lengths is misplaced.

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7/19/2016 7:31 AM

SJP wrote:

I'm sorry, but you think moving ankles back and forth by 0.6" has a similarly large effect on weight distribution to leaning your upper body back and forth? It does not. Secondly, people do play with ankle position by moving their cleats on their shoes, most of which have a range that is a good fraction of that 0.6".

CS length changes the general weight balance of the bike, irrespective of body position? Again, 0.6" change in chainstay length, keeping wheelbase the same, has a very small effect on weight distribution compared to changing upper body position.

Longer reach drives the upper body forward? Not if you shorten the stem to keep the handlebars in the same place, which is how things are typically done. Sure, it lightens the load on the front wheel for a given angle of ground slope, but different people want their bikes optimized for different slopes.

Sure, you can overdo it with long reach or head tube angle, or chainstay length, or any design parameter. But, for the whole crop of modern bikes, these come down to preferences. Heck, just look at the change in weight distribution between flat ground, a 5 degree downslope, and a 10 degree downslope. It is bigger than swapping 0.6" of front-center for 0.6" of rear-center. Different people want their bikes optimized for different things, and ranting against some current bikes' chainstay lengths is misplaced.

Haha, ok, now we're into who said what terrain. If you move the ankle on a horizontal plane, you angle the complete legs differently. Probably you're also moving the lower torso (the ass) a bit into that direction. Maybe the word "similiarly" was too strong, but it will have a substantial effect. You confirm that by saying that people DO play with ankle position. Although I never heard about that in the context of weight balance on the bike, it's usually people wanting to eke out pedalling performance or trying to calm down knee issues (just go flat). But ok, I'm happy to learn sth new.

Yes, irrespective of body position. All things equal (front center, WB, HA, and so on), the CS length determines the leverage that each wheel sees, without the body changing position. Shorten the CS, the back wheel shifts more underneath your ass --> more weight on the back, less on the front (both wheels always add up to 100%, duh). Lengthen the CS, back wheel sees less of your weight, automatically front wheel sees more. Nothing to discuss here, basic static mechanics. All other geometry equal, your body position doesnt change with CS length, that's why I said "irrespective". It does with reach though.

Shortening the stem with a longer reach is even more counter productive, if you want to get more weight on the front wheel. Because then you are simply moving the front wheel away from you without changing your upper body position. Mute argument anyway, cause we need to talk about change in one measure at a time, not multiple ones simultaneously. I was talking about change in reach only.

Your last paragraph has some truth in it. Yes, all these ambient changes are much more drastic. But I'm saying for the third time now, that frame geometry gives the baseline from which the rider reacts to ambient changes like downslope. So yes, it does make a difference, otherwise we would all still ride clunkers from Joe Breeze times or, worse, early '90 long-stem hillbillies.

Also, the OP did not rant about anything. He made an observation, which I can support:
2014, switching from Canyon Torque DHX (425 CS and 394 reach) to Glory (442 CS and 404 reach) was simply great. No more washing out front wheel, when I didnt lean all the way (and then some more) forward on the bike. Suddenly I was able to attack turns. Your experience is different? Be happy with it!

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7/19/2016 8:38 AM
Edited Date/Time: 7/19/2016 8:52 AM

Few thoughts to add but before I do I should apologize for this coffee fueled rant. There were a few things I wasn't overly clear on and others I may have blown out of proportion. Unfortunately, I drank more coffee - so this is just as likely to garner a few eye rolls. Apologies in advance...

First, short chainstays (less than 17) often makes sense for smaller sized bikes. My title (short chainstays suck) wasn't really the point, what the title should have been was "chainstays need to be in proportion to the rest of the bike." In shorter reaches, 16.8-17" stays may make for a really balanced ride, but I can't comment being I ride 18.5-19" reach (XL) bikes.

Second, as much as its a throwback to a time I'd prefer not to revisit, adjustable chainstays could really make sense. Yes, I know, it changes your travel/leverage ratio too, but perhaps there is another way to do this that keeps travel the same (like how they lengthened the V10 without changing travel). Or maybe that's too complicated.

As far as SLP's comments about 0.6" not mattering, ankle position, the human head etc etc I guess all I can say is different strokes for different folks. How tall are you SLP? What size do you ride? I have a hunch you may be on a fairly balanced bike as is. (smaller size than me) Or maybe you are an outliar who likes a 40/60 weight distribution. Or you ride in Virgin Utah at the Rampage site

Again, to say I'm like Gwin, Minnaar, Hill etc is laughable at best. But for all three of these riders going to longer rear centers has helped their results immensely. Could they ride shorter rear ends? Absolutely! I'm just saying they certainly seem to be able to do everything better on more well balanced bikes.

With respect to my 27.5" trail bike, I'd like my chainstays to go from 16.9" to 17.7" and I'd like my reach to be shortened just a hair too. (about 1/2").

Will this change the bike? Absolutely. We all agree one or two degrees of headtube angle either way make a big difference, a few mm of fork offset make a big difference, 0.6" of travel can make a big difference - so why would it surprise any of us that a few mms of rear center can also change the bike's handling and weight distribution an incredible amount. In my experience, a little length here or there can make a big difference (that's what she said) as to how the bike feels..

To be clear, I'm not saying I "can't ride a bike with 16.9" stays and long reach". I'm just saying I have to fight the bike a bit more than I'd like when trying to ride fast for extended periods of tim. I don't feel well situated in my normal "neutral" position between the two wheels and the scales seem to objectively explain this. I can certainly find this position, but its an awkward position, one where I lose a fair amount of leverage and handling precision. Hence, this post.

Here is the kicker, some riders might be naturally in a good position and like the feel of short stays. And therein lies the problem. The human body is so different person to person. When we can adjust headtube angle (werks/angelset) stem, fork travel, stack height, bar height, to some extent bottom bracket etc but are completely limited when it comes to CSs it leaves many riders on bikes that don't quiet suit them, which again brings me back to "I want an adjustable rear end" comment...

Maybe a company should consider building a bike built for racing alone. Leave playfulness to other models. I see this in other sports. Skiing, sleds, moto etc. I realize the smaller companies couldn't do it, but the larger ones could do a "gravity special" with longer stays in the larger sizes and maybe higher end stiffer valved suspension.

But yeah, now I'm **really** getting carried away.

Thanks to everyone for indulging me in my rant! Good (bike nerd) stuff!!!



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7/19/2016 9:09 AM

18" chainstays on 2004 bighit with 26" rear wheel......very quick....but heavy

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